These devices are, in particular, portable items such as smart cards having application programs relating to the fields of health, mobile telephony, as well as banking transactions.
Such smart cards comprise a card body into which an electronic unit is integrated, which contains, in a conventional way, a control unit (such as a central processing unit or CPU) and a memory. This memory comprises at least one application program containing unitary elements which are assigned values so that the program can be executed, wherein these elements are not modified when the application program is executed. These elements are referred to as configurable variables.
In view of configuring said variables, the state of the art provides devices that use files containing data assigned to variables in a so-called initialization phase. This initialization phase is necessary for a proper execution of the application program. In order to do so, these devices comprise control means for modifying the values of initialization data within said files and then assigning these data to said variables. When the variables are permanently stored within the memory, they maintain their initial value even if the card is no longer powered.
Although these devices allow an application program to be configured, the initialization values are duplicated within two memory spaces having substantially identical sizes, one of which contains the initialization data files and the other being the memory space allocated to variables which are initialized with said data, which can be problematic because of the limited available memory of smart cards. Moreover, the execution time of such application program is substantially increased, in particular due to the requirement to perform the initialization phase on every execution of the program even if the initialization values have not changed, as the initialization phase is an integral part of the application program. Finally, there are cases where either the application program has no privilege for file access, or the card simply has no file associated with it.